JP2002521552A - Liquid crystal polymer - Google Patents

Abstract

  (57) [Summary] Provided are compounds of formula (I) that can be used in various devices such as liquid crystal devices, piezoelectric devices, pyroelectric devices and optical recording media. Wherein m is at least 5 and not more than 50;₃Is selected from formula (IA). In formula IA, Y is CO or CH₂Wherein n = 1 to 15, and Q is independently COO, OCO, O, S, CH₂And q = 0 to 15, but when q = 0, only one of Q or Z is present, and Z is independently O, S, a single bond, COO, OCO, CH₂, NH, NR, NR¹Where R is C_1-12N-alkyl or C_1-12Wherein the branched alkyl group may be achiral or chiral;¹Is (CH₂)_tE, where t can be 1 to 15 and E is OH, CO₂H, Br, Cl, I, SH, NH₂, N (CH₃) You can choose from H. (A) represents an arbitrary mesogenic group. X₃Are also independently H, OH, OCOR², COOH, CO₂R², (CH₂)_pOH, (CH₂)_pCO₂H,-(CH₂)_pOR²Or-(CH₂)_pCO ₂R²P = 1-20, and R²Is H or C_1-16Alkyl, where R²Is C_2-16The terminal CH when₃The groups can be replaced by Br or Cl. However, at least X₃Is selected from formula (IA).

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to new liquid crystal polymer (LCP) materials, new intermediates, their preparation and their use in devices.

[0002] Liquid crystals can exist in various phases. Essentially, there are three different types of liquid crystal materials, each with a unique molecular arrangement. These types are nematic, chiral nematic (cholesteric) and smectic. There is a wide range of smectic phases, for example, smectic A and smectic C. Some liquid crystal materials have several liquid crystal phases when the temperature changes.
Some have two phases. For example, a liquid crystal material may be cooled from an isotropic phase to the next phase, ie, -isotropic-nematic-smectic A-smectic C-.
It may show a solid.

[0003] Materials having a smectic A (S _A ) phase can exhibit an electroclinical effect. The electroclinical effect is described by S Garoff and R Meyer in Phys. Rev .. Le
tt. , 38, 848 (1977). Electroclinic devices are also described in British patent application GB-2 244 566 A. This particular device uses a surface array that provides a surface tilt within a small range of angles, using the electrograting effect (E
C) Helps overcome the problem of poor alignment of the device.

If the smectic A phase is composed of chiral molecules, it may exhibit an electroclinical effect, a direct relationship of the molecules to the applied electric field. The occurrence of the electroclinical effect of the smectic A phase composed of chiral polar molecules is explained by Garo
It is described as follows by ff and Meyer. Such smectic A
When an electric field is applied parallel to the smectic layer of the phase, the free rotation of the dipoles of the transverse molecules is biased to one side, thus producing a non-zero mean value of the transverse component of the polarization of the molecules. When such a dipole moment is present and combined with molecular chirality, the tilt of its long molecular axis (director) is induced in a plane perpendicular to the dipole moment.

In thin samples, for example 1-3 mm, having a smectic layer inclined or perpendicular to the glass plate, the electroclinical effect is detected at low applied electric fields.

In aligned smectic A samples, the tilt of the orientation vector is directly related to the tilt of the optical axis. The electroclinic effect produces a linear electro-optic response. The electro-optic effect manifests as an effective modulation of the birefringence of the device.

Electroclinical effect (EC) devices are useful, for example, in spatial light modulators that have an output that varies linearly with applied voltage. A further advantage of EC devices is that they have a fast response time, much faster than twisted nematic type devices. One known type of ferroelectric device is bistable. In contrast, EC devices are not bistable and have an output that varies linearly with applied voltage.

[0008] The electroclinic effect is sometimes called a soft mode effect. G Andersson
Appl. Phys. Lett. , 51, 9, (1987).

[0009] Broadly speaking, with regard to the electroclinical effect, it is advantageous that if a small voltage is applied, this results in a large tilt. As the induced tilt increases, the contrast ratio may increase. It would also be advantageous if a large slope could be caused at the lowest possible voltage.

[0010] It is also advantageous if the relationship between the tilt induced by the molecule and the applied voltage is not temperature-dependent. If increasing the applied voltage causes little or no change in the induced slope, the material under test is generally said to exhibit a saturation voltage effect.

S _A ^* refers to a S _A phase that contains a certain proportion of chiral molecules.

A cholesteric liquid crystal or a chiral nematic liquid crystal has a twisted helical structure that can cope with a temperature change through a change in the pitch length of a helix.
Therefore, as the temperature changes, the wavelength of the light reflected from the flat cholesteric structure will change, and if the reflected light encompasses the visible range, a distinct change in color will occur with the change in temperature. . This means that there are many possible applications, such as in the areas of thermography and thermo-optics.

The cholesteric mesophase differs from the nematic phase in that the cholesteric phase has a helical distortion although the orientation vector is not constant in space. The length of the helix pitch is a measure of the distance when the orientation vector rotates 360 °.

[0014] By definition, cholesteric materials are chiral materials. Cholesteric materials can also be used as dopants in electro-optical displays, for example certain twisted nematic displays, where they can be used to remove twisted defects. The cholesteric materials can also be used in cholesteric to nematic colored phase change displays, where they can be used to increase contrast by preventing waveguiding.

[0015] Thermochromic applications of cholesteric liquid crystal materials typically use preparations of thin films of that material as seen against a black background. These temperature sensing devices may be installed in some applications such as thermometry, medical thermography, non-destructive testing, radiation sensing, and for decorative purposes. These examples can be found in Critical Reports on Applied, edited by GW Gray
Chemistry, Vol. 22, pp. 120-144, 1987, Thermotropic Liquid Cr of DG McDonnell.
ystals. This reference also contains a general description of thermochromic cholesteric liquid crystals.

In general, commercial thermochromic applications require a mixture of formulations having a low melting point, short pitch length and smectic transition just below the required temperature sensing range. Preferably, the mixture or material should retain a low melting point and a high smectic-cholesteric transition temperature.

In general, a thermochromic liquid crystal device has a cholesterogen thin film sandwiched between a transparent support substrate and a black absorbing layer. One such method involves encapsulating the liquid crystal in a polymer, making an "ink" containing the liquid crystal, and applying it to the supporting substrate using printing techniques. Methods for producing the inks include microencapsulation of gelatin in U.S. Pat. No. 3,585,318, U.S. Pat.
1,039 and 3,872,050 polymer dispersions. One method for preparing a thin film structure with well-ordered cholesteric liquid crystals involves laminating the liquid crystal between two embossed plastic sheets. This technique is described in British Patent No. 2,143,323.

Ferroelectric smectic liquid crystal materials that can be produced by mixing an achiral host and a chiral dopant are graded chiral smectic C, F, G, H, I
, J and K phases are used. The chiral smectic C phase is S _C ^* represented by an asterisk indicating chirality. S _C phase is generally considered the most viscous is the most useful for low. Ferroelectric smectic liquid crystal materials ideally last over a wide temperature range, including low viscosity, controllable spontaneous polarization (Ps), and ambient temperature, and are chemically and photochemically stable. It should have the S _C phase exhibiting sex. Materials with these properties give prospects for devices with very fast switching liquid crystals. Applications of ferroelectric liquid crystals are described in Opt. E
ng. JS Patel and JW Goodby, 1987, 26, 273.
Described by:

In a ferroelectric liquid crystal device, its molecules switch between different alignment directions depending on the polarity of the applied electric field. These devices can be configured to exhibit bistability where the molecule tends to remain in one of the two states until it is switched to another switched state. Such a device is described, for example, in US Pat.
As described in US Pat. No. 1047, U.S. Pat. No. 4,368,924, and U.S. Pat. This bistable allows for multiple addressing of very large and complex devices.

One common multiplex display has display elements, ie, pixels arranged in an X, Y matrix recording format, for example, for display of alphanumeric characters. The matrix recording scheme is provided by forming the electrodes as a series of tandem electrodes on one sliding surface and as a series of rows of electrodes on another sliding surface. Each matrix intersection forms an addressable element or pixel. Other matrix layouts are known, such as, for example, a seven bar numeric display.

There are many different multiplexing addressing schemes. Common features include the application of a voltage called a strobe voltage to each column or line in turn. At the same time as the strobe applied to each column, an appropriate voltage, called the data voltage, is applied to the electrodes in all columns. The differences between the different schemes are in the form of strobe and data voltage waveforms.

For other addressing schemes, see GB-2, 146, 473-A, GB
−2,173,336-A, GB-2,173,337-A, GB-2,173
, 629-A, WO 89/05025; I. D. P
aper, 8.4, pages 131-134, by Harada et al.
. D. R. C. Pages 213-221 by Lagerwall et al.
In 1988, I. D. R. C. Addressing, pages 90-101
for Ferroelectric LC Display Panel
s is described by P Maltese of Proc.

The material can be switched between its two states by two strobe pulses of opposite sign along with the data waveform. A blanking pulse can also be used to switch the material to one of its states. Periodically, the sign of the blanking pulse and strobe pulse can be changed to maintain a net DC value.

Because these blanking pulses are typically larger in amplitude and length than the strobe pulse, it does not matter whether one of the two data waveforms is applied to any one intersection. No, the material switches. The blanking pulse can be applied by the line base ahead of the strobe on the line,
Alternatively, the entire display can be turned off at once, or a group of lines can be turned off at the same time.

[0025] In order to achieve the highest performance of the device, it is important to use a mixture of compounds that gives a material with ferroelectric smectic properties which is most suitable for a particular type of device Are well known in the field of ferroelectric liquid crystal device technology.

By considering the response time versus the pulse voltage curve, the device can be evaluated for speed. This relationship can indicate the minimum value (t _min ) of the switching time at a specific applied voltage (V _min ). Higher than V _min or lower voltage, the switching time is longer than _{t min.} It is well understood that devices having such a minimum response time versus voltage curve can be operated and multiplexed at a high duty cycle with a higher contrast than other ferroelectric liquid crystal devices. Preferably, said minimum of the response time versus voltage curve occurs at a low applied voltage and a short pulse length, respectively, so that the device will be operated using a low voltage source and a fast frame address playback speed. .

Representative known materials (materials that are mixtures of compounds with suitable liquid crystal properties) that do not tolerate such a minimum when included in ferroelectric devices include SCE1
3 and ZLI-3654 (both Merck UK, Poole, Dorset)
Ltd. Commercially available materials known to be available from S.A.
Devices exhibiting such a minimum can be assembled according to PCT GB 88/01004 and utilizing materials such as, for example, the commercially available SCE8 (Merck UK Ltd). Another example of prior art materials is PCT GB.
86/00040, PCT GB 87/00441, and British Patent No. 2
Illustrated by 232416B.

The units that are the basic building blocks of a polymer are called monomers.

The polymerization process, ie, the formation of a polymer from its constituent monomers,
Usually, a polymer of uniform molecular weight is not produced, but rather a distribution of molecular weights. In order to describe a sample of a polymer, it is necessary to state the average number of monomers in the polymer, which is called the degree of polymerization (DP). How much of a polymer molecule differs from this average (or describes the spread of molecular weight) is called polydispersity.

For a given sample containing M _n -number average molecular weight and M _w -weight average molecular weight,
Several different average molecular weights can be determined from gel permeation chromatography (GPC). The value used to calculate the degree of polymerization is usually M _n and polydispersity is commonly defined as M _w / M _n .

Polymers can be made from different types of monomers, in which case the polymer is called a copolymer. If two monomers combine in a random fashion, the polymer is called a random copolymer. When the two monomers first form one type of short sequence and then combine to form the final polymer, a block copolymer is formed. If one short sequence of monomers is attached as a side chain to a long sequence of other types of monomers, the polymer is called a graft copolymer.

In liquid crystal (LC) polymers, the monomers can be linked together in essentially two ways. The liquid crystal portion or mesogenic unit of the polymer can be part of the backbone of the polymer that results in a backbone liquid crystal polymer. Alternatively, the mesogenic unit can be attached as a group attached to the polymer backbone, ie, extend away from the polymer backbone.
In this case, a side chain type liquid crystal polymer results. These different types of polymer liquid crystals are shown schematically below. Mesogenic units are depicted by rectangles.

[0033]

Embedded image

The side-chain liquid crystal polymer is generally, along its length, as shown in the schematic below:
It can be thought of as including a flexible polymer with rigid portions (mesogenic units) joined in its length by short flexible (or rigid) units. It is a rigid part of the anisotropy of the mesogenic unit that represents the state of alignment in the liquid crystal phase. There are a number of features that can be varied to affect the phase exhibited by the liquid crystal and subsequent optical properties. Some of these features are particularly related to side-chain liquid crystal polymers. One of these features is the flexible moiety that attaches the mesogenic unit to the polymer backbone, commonly called a spacer group. The length and flexibility of this spacer group can be varied.

[0035]

Embedded image

A number of side-chain liquid crystal polymers are known. For example, GB 2146787
See A.

[0038] Liquid crystal polyacrylates are one known type of liquid crystal polymer (LPC). Liquid crystal polymers are known and used in electro-optical applications, such as pyroelectric devices, non-linear optical devices and optical storage devices. For example, GB 2146787,
And Makromol. Chem. (1985) 186, pages 2639-47.

[0038] The side chain type liquid crystal polyacrylate is manufactured by Polymer Communication.
ns (1988), pages 24, 364-365, for example, describes the following equation:

[0039]

Embedded image Where (CH ₂ ) _m is a flexible spacer group, X is a side chain mesogenic unit, and R is hydrogen or alkyl.

The side-chain liquid crystal polychloroacrylate is described in Makromol. Chem. Rap
id Commun. (1984), 5, pp. 393-398, for example, describes the following equation.

[0041]

Embedded image Here, R is chlorine.

Patent application PCT GB 94/00662 describes, inter alia, the use of the Baylis-Hillman reaction to make a wide range of new liquid crystal polymers.

A method for preparing a homopolymer or copolymer of a polyacrylate having the following repeating units is described in British Patent Application GB 9203730.8.

[0044]

Embedded image

R ₁ and R ₂ are independently an alkyl group or hydrogen, and R ₃ is an alkyl group,
Hydrogen or chlorine, m is 0 or an integer of 1 to 20, and W is CO
O or OOC or O, and X is a mesogenic group.

One of the main problems with liquid crystal polymers is that aligning the liquid crystal polymer in the device is extremely difficult. In essence, there are two techniques used to align liquid crystal polymers. It is possible to attempt to align the liquid crystal polymer in a manner similar to low molar mass liquid crystals, which is described in more detail below. Alternatively, mechanical techniques such as shearing can be used. Typical mechanical shear is performed on a heated roll. This technique is generally only suitable for flexible substrates. The sample can be sheared in the middle of the glass slip surface, but the glass slip surface cannot be sealed in a conventional manner.

[0047] World Scientific Publishing Co, Pte.
Ltd. Liquid Crystals Ap edited by Bahadur, Inc.
Applications and Uses, Volume 1, 171-19, 1990
Materials and Assembly Processes for Liquid Crystal Displays by Morozumi on page 4 and references therein (Materials and Assembling Pro).
ses of LCDs), as the title suggests, discusses how to assemble liquid crystal devices.

The technique for aligning low molar mass liquid crystals is generally as follows. A transparent electrode is formed on the surface of the substrate. The substrate is generally made of glass, for example a sliding surface of glass. In twisted or extremely twisted nematic devices, for example, an alignment process is required for both substrates. Liquid crystal molecules are aligned by depositing a thin alignment layer. Generally, an organic or inorganic alignment layer is used, for example, SiO deposited by evaporation is a typical inorganic alignment layer. One method of forming the alignment layer involves polishing the surface with a fabric or cloth. Polyimide has also been employed for surface alignment of the layers. Polyimide is applied by spinner onto the substrate with the electrodes and then cured to approximately 50 nm
Form a layer of thickness. The surface of each layer is then repeatedly polished with a suitable material in substantially one direction. If liquid crystal molecules have been deposited on this layer, they will automatically align in the direction they were polished. It is often preferred that the molecules have a small angle of pretilt, typically a few degrees. Sometimes higher pretilts are needed.

The two substrates are then fixed together, for example by an adhesive, and kept separate by a spacing material. The result is a uniform and accurate cell spacing. A typical adhesive is an epoxy resin. This sealing material is usually pre-cured at that time. The electrodes are then accurately aligned, for example, to form display pixels. The cell is then cured, for example, at 100-150 ° C. At this point, the empty liquid crystal cell is complete.

At this time, the cell is filled with a liquid crystal material. The size of the opening in the sealed area of the liquid crystal cell is rather small, so that the cell can be emptied, for example, into a vacuum chamber. Then, the liquid crystal material is pushed into the cell by gas pressure. More than one hole in the sealing area may be used. Put the empty cell in the vacuum chamber,
Then pump out the vacuum chamber. After the cell is emptied, the open face of the filler is immersed in the liquid crystal material and the vacuum chamber is returned to normal pressure. The liquid crystal material is
It is drawn into the cell as a result of capillary action. The pressure can be increased by using an external gas. Upon completion of the filling process, the filler hole (s) are capped and the cell is cured at a temperature above the clearing point of the liquid crystal material to stabilize the alignment of the liquid crystal molecules, The material with the lid is cured.

Polymeric liquid crystal molecules tend to be more viscous than low molecular weight liquid crystal materials, and are therefore more difficult to align and more difficult to fill into devices.
Only low molecular weight liquid crystal polymers can flow into the cell. And, once a degree of polymerization of greater than about 30 or 40 repeat units is achieved, most liquid crystal polymers become very viscous and very difficult to fill into the cell. To try and align liquid crystal polymers, very slow cooling is required, which usually results in poor alignment uniformity.

Poorly aligned liquid crystal molecules do not result in the generally required fast switching, high contrast materials and devices.

The techniques described above exhibit a smectic mesophase, for example, a ferroelectric, and are suitable for many liquid crystal materials, such as devices using liquid crystal materials to utilize. A suitable alignment technique is GB 22
10469B.

Devices containing ferroelectric liquid crystal mixtures have fast switching times (faster than 100 ms)
Clark and Lagerwall, Appl. Phys
s. Lett. , 36, 89, 1980. They can be bistable,
It can be multiplexed at a high level using one row at a time scanning technology
Means that Ferroelectric materials are used in high resolution flat panel displays
Therefore, it has been receiving much attention as a research subject. Equipment containing liquid crystal material
An important feature of the devices is that they will exhibit fast response times. That
Response time depends on a number of factors. One of them is the display of spontaneous polarization.
Ps (nCcm^-2Is measured). Liquid crystal mixture with chiral dopant
Increase the value of Ps and thus reduce the response time of the device.
Can be reduced. A mixture of achiral host and chiral dopant
The ferroelectric smectic liquid crystal material that can be formed is an inclined chiral smectic C
, F, G, H, I, J, and K phases are used. Chiral smec
The tic C phase is represented by an asterisk indicating chirality, S_C ^*Is displayed. S_C ^*The phase is the most
Are also considered to be most useful because they also have a fast switching action. liquid
In order to promote the surface alignment of devices containing crystalline materials, the materials must be
Longer pitch chiral nematic (N^*) And S _A It is desirable to show phases. Ideally, the ferroelectric smectic liquid material is
Survive over a wide temperature range, including ambient temperature, of course, chemical and photochemical
Controllable Ps and S with the following properties exhibiting mechanical stability:_C ^*Should have a phase
is there. Materials with these properties can be used in devices containing very fast switching liquid crystals.
Give expectations about

Jitao et al., In Polymer, Vol. 5, 837-1996
Page 841 describes, among other things, the use of diallylamines for the synthesis of hypernucleophiles.

[0056] World Scientific Publishing Co. Pte.
Ltd. Liquid Crystals Ap edited by Bahadur, Inc.
Volumes 350-3 of applications and Uses, Volume 1, 1990
Dijon's ferroelectric liquid crystal display at page 60 and references therein discusses the alignment process of smectic phases for low molar mass materials. Cell filling appears to be possible only with the isotropic or nematic phase due to the viscosity of the smectic phase. In general, materials with the following phase sequence are well-ordered.

[0057]

Embedded image

In contrast, materials with the following phase sequence are more difficult to align.

[0059]

Embedded image

Therefore, in general, in order to use a liquid crystal material in a smectic phase, it is necessary to heat the material to a nematic phase or an isotropic phase and slowly cool it to an ordered smectic state. there will be. When applying this technique to polymer liquid crystal materials, the cooling time is then usually very long to help with the alignment. Nevertheless, the sequences are very often inadequate.

There is a continuing need for new liquid crystal polymers that have properties that allow them to be used in devices that include one or more of the known electro-optical devices.

According to the present invention, there is provided a material of general formula I:

[0063]

Embedded image In the above formula, m is at least 5 and 50 or less, and X ₃ is selected from Formula IA.

[0064]

Embedded image

Here, Y is selected from CO or CH ₂ , n = 1 to 15, Q is independently selected from COO, OCO, O, S, CH ₂ , and when q = 0, Q is Or q = 0 to 1 under the condition that only one of Z exists
And Z is independently selected from O, S, a single bond, COO, OCO, CH ₂ , NH, NR, NR ¹ , wherein R is C _1-12 n-alkyl or C _1-12 And the branched alkyl group can be achiral or chiral, R ¹ is (CH ₂ ) _t E, t can be 1 to 15, and E is OH, CO ₂ H,
It can be selected from Br, Cl, I, SH, NH ₂ , N (CH ₃ ) H;

[0066]

Embedded imageRepresents any mesogenic group; X₃Are also independently H, OH, OCOR², COOH, CO₂R², (CH ₂ )_pOH, (CH₂)_pCO₂H,-(CH₂)_pOR², Or-(CH₂ )_pCO₂R²And p = 1-20, R²Is H or C_{1 to 16} Alkyl, where R²Is C_2-16Terminal CH when alkyl ₃ The groups may be replaced by Br or Cl, provided that X₃At least one is selected from Formula IA.

[0067] Mesogenic groups are further defined by the general structure II.

[0068]

Embedded image

A, B and D are selected from the following rings:

[0070]

Embedded image

The ring may have at least one of the available substitution positions
One or more substituents, _{namely, F, Cl, Br, CH} 3, CN, OR, R and NCS (R is alkyl branched or straight-chain _{C 1 to 5)} can be replaced with, Z is CN, F, Cl, NO ₂ , R, OR, CO ₂ R, CF ₃ , OOCR, N
Selected from CS and SCN, wherein R is straight or branched chain alkyl,
It may contain 16 carbon atoms and one or more non-adjacent CH ₂ groups may be CH (CN), CH (CF ₃ ), CH (Cl), in chiral or achiral form.
Including the case where CH (CH ₃ ) can be substituted, provided that the total number of rings is 4 or less, and W ₁ and W ₂ are COO, OCO, a single bond, CH ₂ CH ₂ , CH ₂ O, OC
_{H 2, O, S, CH} = CH, C≡C, OCO (CH 2) X, is independently selected from COO _{(CH 2) X,} where, x is 1 to 4.

The liquid crystal polymers described by the present invention may be of any known type, including homopolymers or copolymers.

[0073] Y in Formula IA may be CHOH, the OH group of which is used as the point of attachment of the crosslinker to form an elastomer.

According to another aspect of the present invention, liquid crystal polymers of general formula I can be synthesized by cyclization of a suitably functionalized diene.

According to another aspect of the present invention, a liquid crystal polymer of general formula I and variants thereof are
It can be synthesized by cyclization of the following general formula III.

[0076]

Embedded image

According to another aspect of the present invention, a material is provided for Formula I wherein a portion of the repeating units are made up of the following general formula IIIA:

[0078]

Embedded image

According to another aspect of the present invention there is provided a compound of formula III:

[0080]

Embedded image Here, _{X 3} is selected from formula IA.

The present invention is described below, by way of example only, with reference to the drawings.

FIG. 1 is a general synthetic scheme for the preparation of polymers of general formula I. FIG. 2 is a general synthetic scheme for the preparation of polymers of general formula I when q = 0. FIG. 3 is a general synthetic scheme for polyamide production. FIG. 4 is a general synthetic scheme for polyamine production. FIG. 5 is a diagram illustrating a liquid crystal device. FIG. 6 shows a pyroelectric device. 7 and 8 are front and cross-sectional views, respectively, of a reflective spatial light modulator depicted at different scales that can incorporate the materials of the present invention.

The following reagents were used in FIGS. Schemes 1-4 relate to FIGS. 1-4, respectively.

Scheme 1 is a general scheme for the preparation of a polymer of Formula I; Scheme 2 is a scheme for the preparation of a polymer of General Formula I when q = 0; Scheme 4 is a general scheme for the preparation of a polyamine, wherein DCC is dicyclohexylcarbodiimide and DMAP is dimethylaminopyridine.

The reagents of Scheme 1, steps ad, and the reagents used in scheme 2, steps ac, are selected from standard methods in the literature.

Reagents used in the experimental schemes are commercially available from Aldrich, unless otherwise specified.

The following examples illustrate the methods used in Schemes 3 and 4 to prepare cyclic poly (amides) and poly (amines), respectively.

The structures of all compounds were determined by nuclear magnetic resonance spectroscopy (JEOL JNM-GX-270).
MHz spectrometer), infrared spectroscopy (Perkin-Elmer 783 grating spectrophotometer), and mass spectrometry (Finnigan-MAT 1020G / MS spectrometer). Compound purity was determined by thin layer chromatography (single spot) or by high performance liquid chromatography (5 μm, 25 × 0.4
6 cm, ODS Microsorb column, methanol,> 99%) and, in the case of SCLC polymers, gel permeation chromatography [5 μm, 3 μm,
0 × 0.75 cm, 2 × mixed DPL column, polystyrene standard (Mp = 100
0-430500), toluene, but no monomer present]. The transition of the liquid crystal phase is determined by differential scanning calorimetry (DSC).
(Perkin-Elmer DSC7 with data station and cooling accessories
). The liquid crystal phase was confirmed by light microscopy (Olympus BH2 polarizing microscope with Mettler FP52 exothermic stage and FP5 controller).

Scheme 3, Step 3a Diallylamine (0.052 mol) in dry dichloromethane (75 cm ³ )
, 11-bromoundecanoic acid (0.052 mol), dicyclohexylcarbodiimide (DCC) (0.055 mol) and N, N-dimethylaminopyridine (DMAP) (0.25 g) were stirred together at room temperature for 6 hours. After removal of the dicyclohexyurea by filtration, the solvent was removed in vacuo, leaving a yellow oil. The oil solidified on standing. Recrystallization from butanone gave compound 1 (85%) with white needles and a melting point of 40-42 ° C.

[0090]

Embedded image

Scheme 3, Step 3b Bromodiallylamide (1) (0.0058 mol), 4-cyano-4′-hydroxybiphenyl (0.0058 mol), and potassium carbonate (3.0 g)
Were refluxed together in dry butanone (60 cm ³ ) for 24 hours. The excess potassium carbonate was filtered off, followed by removal of the solvent in vacuo, leaving a white solid. The solid was purified by column chromatography (silica gel) using ethyl acetate as eluent. Recrystallization from acetonitrile provided compound 2 (89%) as a white powder, mp 61-63 ° C.

[0092]

Embedded image

Scheme 3, Step 3c Monomer (2) (0.0018 mol) and Irgacure 184 photoinitiator (Ciba-Geigy) (0.01 mmol) were added to dry dichloromethane (3
. 0 cm ³ ). The resulting solution was then spread evenly on a borosilicate glass plate (25 × 18 cm ² ). The solvent was evaporated into air, leaving a film of monomer. A similar glass plate was placed on top of the monomer film. The two plates were then pressed together to create a very thin film between the plates. The "sandwich" of the monomer is then
Illuminated under a Philips UVA (70 watt) sun light for 30 minutes. The resulting polymer was removed from the plate, suspended in methanol and centrifuged (11,000 rpm for 10 minutes). The centrifugation was repeated three more times, then the polymer was dissolved in dry dichloromethane (10 cm ³ ). The resulting solution was passed through a 0.5 μm filtration membrane. Removal of the solvent gave cream colored solid polymer 3 (50%).

[0094]

Embedded image

Scheme 4, Step 4a 11-Bromo-1-undecanol (0.001 mol) and diallylamine (
(0.052 mol) were refluxed together for 2 hours. The reaction mixture was added to brine (2
00 cm ³ ) and the resulting mixture was extracted with dichloromethane (2 × 50 cm ³ ). The organic phase was then dried over magnesium sulfate. The solvent was removed in vacuo to leave a brown oil, which was then distilled under reduced pressure (87 ° C./0.5 m
mHg) to leave compound 4 as a colorless oil (80%).

[0096]

Embedded image

Scheme 4, Step 4b 11-Diallylaminoundecane-1-ol (4) (3.7 mmol), 3
-(4'-undecyloxybiphenyl) propanoic acid (3.7 mmol), dicyclohexylcarbodiimide (DCC) (3.9 mmol) and N, N-dimethylaminopyridine (DMAP) (0.15 g) Stirred together in dry dichloromethane (60 cm ³ ) at room temperature for 24 hours. The resulting mixture was filtered to remove dicyclohexyurea and the solvent was removed in vacuo, leaving a white solid. Column chromatography on silica gel using a 1: 1 mixture of ethyl acetate: petroleum fraction (boiling point, 40-60 ° C.) as eluent, followed by recrystallization from acetonitrile to give a white waxy solid. Was 90 ° C. (70%).

[0098]

Embedded image

Compound 5 was prepared according to Mol. Cryst. Liq. Cryst. , 1994, 25
It was synthesized according to an appropriate synthesis method shown in Vol.

Scheme 4, Step 4c Monomer 6 (1.6 mmol) and Irgacure 184 photoinitiator (Cib
a-Geigy) (0.008 mmol) in dry dichloromethane (3.0 cm). ³ ) And dissolve the resulting solution in a borosilicate glass plate (25 × 18c).
m²) On top of it. Solvent evaporated into air, leaving a film of monomer
. A similar glass plate was placed on top of the monomer film. And the two
The plates were pressed together, resulting in a very thin film between the plates
. The "sandwich" of the monomer is then applied to the Philips UV for 30 minutes.
Illuminated under A (70 watt) sun light. The resulting polymer is
The suspension was removed from the solution, suspended in methanol, and centrifuged (11,000).
At 0 rpm for 10 minutes). Centrifugation was repeated three more times. Then the polymer
-Dry dichloromethane (10cm³). The resulting solution was added to 0.
It was passed through a 5 μm filtration membrane. When the solvent is removed, the polymer is a cream colored solid
7 was obtained (54%). Transition (° C.): g 57.0 S_C 68.0 l.

[0101]

Embedded image

Specific examples of the compounds produced by the methods described in Schemes 3 and 4 are as follows.

[0103]

Embedded image

[0104]

Embedded image

Next, an example of the use of materials and devices embodying the present invention will be described with reference to FIG.

The liquid crystal device comprises, for example, two transparent plates 1 and 2 made of glass. These plates are covered on their internal surfaces with transparent conductive electrodes 3 and 4. Alignment layers 5 and 6 are introduced on the inner surface of the cell such that the planar orientation of the molecules making up the liquid crystal material is approximately parallel to the glass plates 1 and 2. This is done by completely covering the glass plates 1, 2 with conductive electrodes such that the intersection between each row and column forms an x, y matrix of addressable elements or pixels. For some displays,
The arrangement direction is orthogonal. Prior to the construction of the cell, the layers 5, 6 are applied to a fabric (eg,
Polish in the given direction with a roller covered with a velvet cloth). The polishing direction is arranged parallel (same or opposite direction) to the cell configuration. For example, a polymethyl methacrylate spacer 7 separates the glass plates 1 and 2 by a suitable distance, eg, 2 microns. The liquid crystal material 8 is introduced by filling the space between the glass plates 1, 2. This is done by inflow filling the cell using standard techniques. Using the existing technology, the spacer 7
Seal with adhesive 9 in vacuum. Polarizers 10, 11 can be placed before and after the cell.

The alignment layer may be coated on one or more cell walls by one or more standards, such as by polishing or indirect evaporation, or as described above by using a polymer alignment layer. It can also be introduced by conventional surface treatment technology.

In another embodiment, the substrate on which the layers are arranged is heated and sheared to introduce the arrangement. Alternatively, the substrate on which the layers are arranged is thermally baked at a temperature higher than the glass transition temperature and lower than the liquid crystal for an isotropic phase transition in combination with the applied electric field. Furthermore, combinations may include combinations of these arrangement techniques. Certain of these combinations may not require an alignment layer.

[0109] The device may operate in a transmission mode or a reflection mode. In the former, for example,
Light from the tungsten bulb passing through the device is selectively sent or blocked to form the desired display. In the reflection mode, a mirror or diffuse reflector (12) is placed behind the second polarizer 11 to reflect ambient light back through the cell and the two polarizers. By partially reflecting with a mirror, it is possible to operate the device in both transmission and reflection modes.

The array layers 5 and 6 have two functions. One is to arrange the molecules of the liquid crystal in contact in a preferred direction, and the other is to tilt the molecules several degrees, typically about 4 ° or 5 °-the so-called surface tilt. is there. Array layer 5,
6 can be formed by placing a few drops of polyimide on the cell wall and rotating the wall until a uniform thickness is obtained. The polyimide is then cured by heating to a predetermined temperature for a predetermined time, followed by unidirectional polishing with a roll covered with a nylon cloth.

In another embodiment, one polarizer and a dye material can be combined.

The liquid crystal material 8, when introduced into the cell, may consist of a liquid crystal polymer or may consist of a liquid crystal monomer and a photoinitiator. It may also include reagents that limit the molecular weight of the polymer, such as a chain transfer agent, and may also include a thermal initiator.

Using standard techniques, for example, heating the monomeric material to an isotropic phase and cooling from the isotropic phase or from a liquid crystal phase such as a nematic or chiral nematic phase It is also possible to arrange them before polymerization. The liquid crystal polymer can also be aligned by one or more techniques including the use of surface forces, shear alignment or field alignment.

Even after polymerization, some amount of monomeric material may still remain. This may be an unreacted monomer, or a low molar mass additive without polymerizable groups.

The polymerization may be performed using any known technique. For example, the initiator may be added to the monomer material and exposed to ultraviolet light, or heat may be used to cause polymerization within a given phase of the monomer and / or polymer.

Alternatively, the polymerization process may occur in the presence of heat and a thermal initiator. However, when using this technique, it may be desirable if it is performed at a temperature corresponding to the liquid crystal phase of the monomer material.

In-situ polymerization is described in British Patent Application GB 9420632.3. The patent application also describes the use of a chain transfer agent to control the molecular weight of the liquid crystal polymer. As mentioned above, a chain transfer agent may be present in the mixtures of the present invention. GB 9514970.4 describes polymerizing in situ in the presence of a cationic photoinitiator.

Many of the compounds described by Formula I and mixtures containing compounds of Formula I exhibit liquid crystal behaviour, and are, therefore, effectively employed in liquid crystal devices. Examples of such devices include optical and electro-optical devices, magneto-optical devices, and devices that can respond to stimuli such as temperature changes and changes in total or partial pressure. The compound of formula I may be contained in a mixture. In that case, the mixture includes at least two compounds. A typical mixture includes a mixture comprising a compound of Formula I;
Also included are mixtures comprising at least one compound of the formula I and at least one compound not from the formula I.

Materials have been proposed for laser addressed applications that use a laser beam to scan across the surface of the material or leave a written impression thereon. For various reasons, many of these materials consisted of organic materials that were at least partially transparent in the visible region. The technique is based on the local absorption of laser energy, which produces local heating and in turn changes the optical properties of otherwise transparent materials in the area in contact with the laser beam. Thus, the written result of the passage is neglected as the light beam traverses the material. One of the most important of these applications is in laser-processed optical storage devices and in laser-processed projection displays in which light is directed through cells containing the material and projected onto a screen. Such a device is described by Khan in Appl. Phys. Lett. , Vol. 22, p. 111 of 1973. In Harold and Steele, one in Paris, France.
Proceedings of Euro disp published in September 984
described in lay 84, pages 29-31, in which the material of the device was a smectic liquid crystal material. Devices using liquid crystal materials as optical storage media are an important class of such devices. A semiconductor laser, (be up 1 from where x is 0, preferably 1), especially _Ga x _{Al 1-x} As lasers were found to be popular in the above applications. Because they can provide laser energy in the near-infrared wavelength range that cannot be seen, and thus disturb the visual display, they can provide a useful source of well-defined strong thermal energy Because. Gallium arsenide lasers generate laser light at a wavelength of about 850 nm and are useful for the aforementioned applications. As the Al content increases (x <1), the laser wavelength may be reduced to about 750 nm. By using shorter wavelength lasers, the storage density can be increased.

The compounds of the present invention are suitable as optical storage media, and can also be combined with dyes for use in laser-treated systems, for example, optical recording media.

The smectic and / or nematic properties of the materials described according to the invention can be exploited. For example, the materials of the present invention can be used in ferroelectric mixtures and devices.

The compounds of the present invention can also be used in pyroelectric devices, such as detectors, steering arrays and vidicon cameras.

FIG. 6 illustrates a simple pyroelectric detector that can incorporate the materials of the present invention.

The pyroelectric detector consists of electrode plates 1, 2, at least one of which may be pixellated. In operation, the detector is exposed to the radiation R absorbed by the electrode 1, for example infrared. As a result, the temperature rises, which is transmitted by conduction to the layer 3 of pyroelectric material. Changes in temperature result in thermal expansion and the generation of charge. This change in charge is typically small compared to the charge output due to a change in spontaneous polarization Ps with a temperature change. This constitutes the initial pyroelectric effect. A change in the charge results in a change in the potential difference between the electrodes. The charge for each pixel can be read.
The resulting signal is then used, for example, to adjust a scanning circuit in a video monitor and for visual images of infrared scanning.

The selective reflective properties of the materials described by the present invention also allow the materials of the present invention to be used in inks and paints. Therefore, those materials may be useful in operations to prevent counterfeiting. They can also be used for so-called safety inks. Other applications include thermal control management, for example, the material may be included in a paint that may be applied to one or more windows to reflect infrared light.

As shown in FIGS. 7 and 8, the spatial light modulator typically comprises two glass walls 2.
And 3 and a liquid crystal cell 1 formed by spacers 4 having a thickness of 0.1 to 10 μm, for example, 2.5 μm. The inner surface of the wall carries thin transparent indium tin oxide electrodes 5, 6 connected to a variable voltage source 7. Electrode 5,
On top of this is a polished polyimide surface alignment layer 8, for example, described in detail below.
, 9. Other sequencing techniques, for example, are also suitable burnished no techniques such as a SiO ₂ evaporation. A layer of liquid crystal material 10 is included between the walls 2, 3 and the spacer 4. In front of the cell 1 is a linear polarizer 11. On the other hand, behind the cell is a quarter plate 12 (which may be optional) and a mirror 13. An example of a linear polarizer is a polarizing beam splitter (not illustrated here).

There are various electroclinic devices that can incorporate the compounds of the present invention. For example,
In the foregoing description of FIGS. 12 and 13, active black plane driving may be utilized. One of the walls forming the cell may be formed from a silicon substrate, for example, a wafer having circuitry for moving pixels.

In many of these devices, there is an optimal thickness for the cell that is associated with the birefringence (Δn) given by:

[0129]

(Equation 1) Where λ = wavelength of operation, Δn = birefringence of liquid crystal material, m = integer.

Among the suitable methods for driving the electroclinic device described by the present invention include:
Some can be found in British Patent Application GB-2247792A.

The mode of operation of the device described according to the present invention includes either amplitude modulation or phase modulation. Similarly, the device may be used in a reflective or transmissive mode.

The materials of this aspect of the invention can also be used in many known forms of liquid crystal displays, for example, chiral smectic electro-optical devices. Such devices have an electrode structure and a surface that has been treated to align the molecules of the liquid crystal material.
It may also include a layer of liquid crystal material contained between two spaced cell walls.
Liquid crystal mixtures can have many uses, including applications in ferroelectric devices, thermochromic devices, electroclinic devices.

The compounds of the invention can be mixed with one another to form useful liquid crystal mixtures. The compounds can also be used with other liquid crystal polymers or low molar mass non-polymeric liquid crystal materials.

Suitable devices that can incorporate the materials of the present invention include beam steering, shutters,
There are modulators, pyroelectric sensors and piezoelectric sensors.

The materials of the present invention may also be useful as dopants in ferroelectric liquid crystal devices, which may be multiplexed, or they may be used in active backplane ferroelectric liquid crystal systems. . The materials of the present invention may be useful as host materials. The materials of the present invention may be included in a mixture that also includes one or more dopants.

The compounds of formula I can also be mixed with a wide variety of hosts, for example, smectic hosts, to form useful liquid crystal compositions. Such compositions have a range of Ps
Can have a value. The compounds of the formula I can also be mixed with one or more of the classes of the hosts VIII-XIII. These different types of hosts can also be mixed with one another and to which compounds of the general formula I can be added.

Typical hosts include the following:

Compounds of formula VIII described in PC / GB86 / 00040, for example

[0139]

Embedded image

Here, R ₁ and R ₂ are independently a C _{3 to} C ₁₂ alkyl group or an alkoxy group.

For example, the fluoroterphenyls of the formula IX as described in EPA 84304894.3 and GBA 8725928,

[0142]

Embedded image

Wherein R ₁ and R ₂ are independently C ₃ -C ₁₂ alkyl or alkoxy, x is 1 and F is at any of the available substitution positions on the designated phenyl ring Is also good.

For example, difluoroterphenyls of the formula X described in GBA 8905422.5,

[0145]

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Here, R ₁ and R ₂ are each independently a C ₃ -C ₁₂ alkyl group or an alkoxy group.

For example, the phenylpyrimidines of the formula XI described in WO 86/000087

[0148]

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Here, R₁Is C₃~ C₁₂Wherein R is₂Is the general formula (CH₂) _n -CHXCH₂CH₃Where n is 1-5 and X is CN or Cl
It is.

Cyclo at the 16th Freiburg LCD Conference in Freiburg, Germany
Hexanederative mit Getiltenen Sm
E. Merck Ltd., Germany, described by R Eidensink et al. on page 8 of Ektischen Phasen. For example, compounds of formula XII, available from the company

[0151]

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Here, R ₁ and R ₂ may be independently C ₁ -C ₁₅ alkyl.

For example, difluorophenylpyrimidines of formula XIII, described by Reiffenrath et al. At the 2nd International Symposium on Ferroelectric Liquid Crystals in Goteborg, Sweden in June 1989

[0154]

Embedded image

Here, R ₁ and R ₂ may be independently a C ₃ -C ₉ alkyl group.

The materials of the present invention can be used in thermochromic devices, such as those described by G.A. W. Gra
Critical Reports on Applie edited by y
d Chemistry, Volume 22, pages 120-44, Thermochrom.
ic Liquid Crystals and references therein include D.I. G. FIG. Mc
It may also be useful in these devices described by Donnell.

[Brief description of the drawings]

FIG. 1 is a general synthetic scheme for the preparation of a polymer of general formula I.

FIG. 2 is a general synthetic scheme for the preparation of polymers of general formula I when q = 0.

FIG. 3 is a general synthetic scheme for polyamide production.

FIG. 4 is a general synthetic scheme for polyamine production.

FIG. 5 illustrates a liquid crystal device.

FIG. 6 shows a pyroelectric device.

FIG. 7 is a front view and a cross-sectional view of a reflective spatial light modulator drawn at different scales that can incorporate the materials of the present invention.

FIG. 8 is a front and cross-sectional view of a reflective spatial light modulator drawn at different scales that can incorporate the materials of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/3462 C08K 5/3462 C08L 39/00 C08L 39/00 C09K 19/38 C09K 19/38 19/42 19/42 19/44 19/44 19/46 19/46 G02F 1/13 500 G02F 1/13 500 (72) Inventor Hall, Alan William Hal-H-U-J. Etux, University of Hull, School of Chemistry (no street address) , School of Chemistry (No address) F-term (reference) 4H027 BA02 BA13 BD17 CF05 CG05 C Q02 DE03 DE05 4J002 BJ001 ED056 EH126 ET006 EU136 FD206 GP00 GQ00 GS00 4J100 AN14P AT13P BA02P BA03P BA04P BA12P BA15P BA16P BA20P BA28P BA29P BA31P BA40P BA50P BA51P BA52P BB01P11 BCBBPP BCBC BCBC BCBC

Claims (20)

[Claims] 1. Materials of general formula I. Embedded image[Wherein m is at least 5 and not more than 50;₃Is selected from formula IA: Where Y is CO or CH₂Wherein n = 1 to 15, Q is independently COO, OCO, O, S, CH₂When q = 0, q = 0 to 1 under the condition that only one of Q or Z exists.
5, Z is independently O, S, a single bond, COO, OCO, CH₂, NH, NR, NR¹ Where R is C_1-12N-alkyl or C_1-12Branch of a
And the branched alkyl group can be achiral or chiral;
R¹Is (CH₂)_tE, where t can be 1 to 15 and E is OH
, CO₂H, Br, Cl, I, SH, NH₂, N (CH₃You can choose from H)
,Represents any mesogenic group; X₃Are also independently H, OH, OCOR², COOH, CO₂R², (CH ₂ )_pOH, (CH₂)_pCO₂H,-(CH₂)_pOR², Or-(CH₂ )_pCO₂R²P = 1-20, R²Is H or C_1-16Alkyl
Where R²Is C_2-16In the case of alkyl, the terminal CH₃The group is B
can be replaced by r or Cl, where X₃At least one is selected from Formula IA. ] 2. The mesogenic group is represented by the general structure II: A, B, and D are selected from the following rings: The ring, one or more of the following substituents in at least one of the available substitution positions, _{namely, F, Cl, Br, CH} 3, CN, OR, R and NC
S may be substituted with S (R is C _1-5 branched or straight chain alkyl); Z is CN, F, Cl, NO ₂ , R, OR, CO ₂ R, CF ₃ , OOCR, NC
Selected from S and SCN, wherein R is a linear or branched alkyl group,
It may contain 16 carbon atoms and the one or more non-adjacent CH ₂ groups may be CH (CN), CH (CF ₃ ), CH (Cl),
CH (CH ₃ ), wherein the total number of rings present is 4 or less, and W ₁ and W ₂ are independently COO, OCO, a single bond, CH ₂ CH ₂ , CH ₂ O , OCH ₂ , O, S, CH = CH, C≡C. 3. A liquid crystal mixture comprising at least one of the compounds of claim 1. 4. A ferroelectric mixture comprising at least one compound of the formula I. 5. A cholesteric liquid crystal mixture comprising at least one of the compounds of claim 1. 6. A liquid crystal mixture comprising any of the compounds of claim 1 and a material of the following general formula: Embedded image Wherein R ₁ and R ₂ are independently C ₃ -C ₁₂ alkyl or alkoxy. 7. A liquid crystal mixture comprising any of the compounds of claim 1 and a material of the following general formula: Embedded image Wherein R ₁ and R ₂ are independently C ₃ -C ₁₂ alkyl or alkoxy, x is 1 and F is at any of the available substitution positions on the designated phenyl ring Can be] 8. A liquid crystal mixture comprising any of the compounds of claim 1 and a material of the following general formula: Embedded image Wherein R ₁ and R ₂ are independently C ₃ -C ₁₂ alkyl or alkoxy. 9. A liquid crystal mixture comprising any of the compounds of claim 1 and a material of the following general formula: Embedded image [Wherein, R ₁ is C ₃ -C ₁₂ alkyl, and R ₂ has the general formula (CH ₂ ) _n −
CHXCH ₂ CH ₃ (where n is 1 to 5 and X is CN or Cl)
Indicated by 10. A liquid crystal mixture comprising any of the compounds of claim 1 and a material of the following general formula: Embedded image Wherein R ₁ and R ₂ are independently C ₁ -C ₁₅ alkyl. 11. A liquid crystal mixture comprising any of the compounds of claim 1 and a material of the following general formula: Embedded image Wherein R ₁ and R ₂ are independently C ₃ -C ₉ alkyl. 12. A liquid crystal material interposed between two spaced apart cell walls, each having an electrode structure and being provided with an alignment layer on at least one interface, and a liquid crystal material interposed between the cell walls. A device comprising a layer, comprising the liquid crystal mixture according to claim 3. 13. A pyroelectric device comprising two spaced apart electrodes and a layer of liquid crystal material interposed between the electrodes, said pyroelectric device comprising a liquid crystal mixture according to claim 3. A pyroelectric device. 14. A piezoelectric device comprising two spaced apart electrodes and a layer of liquid crystal material interposed between said electrodes, said piezoelectric device comprising a liquid crystal mixture according to claim 3. A piezoelectric device characterized by the above-mentioned. 15. A liquid crystal electro-optical display device comprising the mixture according to claim 3. Description: 16. An optical recording medium comprising a recording layer containing a dye and one or more compounds according to claim 1. 17. A compound of formula III A method for synthesizing the material of claim 1 or 2, comprising the step of polymerizing 18. A portion of the material has the general formula IIIA: The material according to claim 1, wherein the material is composed of: 19. A material of general formula III. Embedded image [Where X₃Is selected from formula IA: Where Y is CO or CH₂Wherein n = 1 to 15, Q is independently COO, OCO, O, S, CH₂When q = 0, q = 0 to 1 under the condition that only one of Q or Z exists.
5, Z is independently O, S, a single bond, COO, OCO, CH₂, NH, NR, NR¹ Where R is C_1-12N-alkyl or C_1-12Branch of a
And the branched alkyl group can be achiral or chiral; ¹ Is (CH₂)_tE, where t can be from 1 to 15, E is OH,
CO₂H, Br, Cl, I, SH, NH₂, N (CH₃) You can choose from H
,Represents any mesogenic group] 20. The mesogenic group is represented by the general structure II: A, B, and D are selected from the following rings: The ring, one or more of the following substituents in at least one of the available substitution positions, _{namely, F, Cl, Br, CH} 3, CN, OR, R and NC
S may be substituted with S (R is C _1-5 branched or straight chain alkyl); Z is CN, F, Cl, NO ₂ , R, OR, CO ₂ R, CF ₃ , OOCR, NC
S, SCN, wherein R is straight or branched chain alkyl, which can contain from 1 to 16 carbon atoms and which may contain one or more non-adjacent C
The H ₂ group may be CH (CN), CH (CF ₃ ), CH (C
l), which may be substituted by CH (CH ₃ ), provided that the total number of rings present is 4 or less, and W ₁ and W ₂ are independently COO, OCO, a single bond, CH ₂ CH ₂ , CH ₂ O, OCH ₂ , O, S, CH = CH, C≡C, OCO (CH ₂ ) _x , COO (C
Selected from H _{2) x,} where x is 1 to 4, material of claim 19.